Print Eigen's Matrix

print_eigen_mat.cpp

void PrintEigenMat(const Eigen::Ref<const Eigen::MatrixXd> &x,
    const std::string mat_name) {
  if (!mat_name.empty()) {
    std::cout << mat_name << " =\n";
  }
  const int rows = x.rows();
  const int cols = x.cols();
  char buf[200];
  for (int i = 0; i < rows; ++i) {
    for (int j = 0; j < cols; ++j) {
      double val = x(i, j);
      sprintf(buf, "%.8lf", val);
      std::cout << "\t" << std::setprecision(9) << buf;
    }
    std::cout << std::endl;
  }
  std::cout << std::endl;
}